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  <section id="cmake-project-compat-version">
<span id="variable:CMAKE_PROJECT_COMPAT_VERSION"></span><h1>CMAKE_PROJECT_COMPAT_VERSION<a class="headerlink" href="#cmake-project-compat-version" title="Link to this heading">¶</a></h1>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 4.1.</span></p>
</div>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>Experimental. Gated by <code class="docutils literal notranslate"><span class="pre">CMAKE_EXPERIMENTAL_EXPORT_PACKAGE_INFO</span></code>.</p>
</div>
<p>The compatibility version of the top level project.</p>
<p>This variable holds the compatibility version of the project as specified in the
top level CMakeLists.txt file by a <span class="target" id="index-0-command:project"></span><a class="reference internal" href="../command/project.html#command:project" title="project"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">project()</span></code></a> command.  In the event
that the top level CMakeLists.txt contains multiple <span class="target" id="index-1-command:project"></span><a class="reference internal" href="../command/project.html#command:project" title="project"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">project()</span></code></a> calls,
the most recently called one from that top level CMakeLists.txt will determine
the value that <code class="docutils literal notranslate"><span class="pre">CMAKE_PROJECT_COMPAT_VERSION</span></code> contains.  For example, consider
the following top level CMakeLists.txt:</p>
<div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">cmake_minimum_required(</span><span class="no">VERSION</span><span class="w"> </span><span class="m">4.1</span><span class="nf">)</span>
<span class="nf">project(</span><span class="nb">First</span><span class="w"> </span><span class="no">VERSION</span><span class="w"> </span><span class="m">9.0</span><span class="w"> </span><span class="no">COMPAT_VERSION</span><span class="w"> </span><span class="m">1.2.3</span><span class="nf">)</span>
<span class="nf">project(</span><span class="nb">Second</span><span class="w"> </span><span class="no">VERSION</span><span class="w"> </span><span class="m">9.0</span><span class="w"> </span><span class="no">COMPAT_VERSION</span><span class="w"> </span><span class="m">3.4.5</span><span class="nf">)</span>
<span class="nf">add_subdirectory(</span><span class="nb">sub</span><span class="nf">)</span>
<span class="nf">project(</span><span class="nb">Third</span><span class="w"> </span><span class="no">VERSION</span><span class="w"> </span><span class="m">9.0</span><span class="w"> </span><span class="no">COMPAT_VERSION</span><span class="w"> </span><span class="m">6.7.8</span><span class="nf">)</span>
</pre></div>
</div>
<p>And <code class="docutils literal notranslate"><span class="pre">sub/CMakeLists.txt</span></code> with the following contents:</p>
<div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">project(</span><span class="nb">SubProj</span><span class="w"> </span><span class="no">VERSION</span><span class="w"> </span><span class="m">2.0</span><span class="w"> </span><span class="no">COMPAT_VERSION</span><span class="w"> </span><span class="m">1.0</span><span class="nf">)</span>
<span class="nf">message(</span><span class="s">&quot;CMAKE_PROJECT_COMPAT_VERSION = ${CMAKE_PROJECT_COMPAT_VERSION}&quot;</span><span class="nf">)</span>
</pre></div>
</div>
<p>The most recently seen <span class="target" id="index-2-command:project"></span><a class="reference internal" href="../command/project.html#command:project" title="project"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">project()</span></code></a> command from the top level
CMakeLists.txt would be <code class="docutils literal notranslate"><span class="pre">project(Second</span> <span class="pre">...)</span></code>, so this will print:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>CMAKE_PROJECT_COMPAT_VERSION = 3.4.5
</pre></div>
</div>
<p>To obtain the version from the most recent call to <span class="target" id="index-3-command:project"></span><a class="reference internal" href="../command/project.html#command:project" title="project"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">project()</span></code></a> in
the current directory scope or above, see the <span class="target" id="index-0-variable:PROJECT_COMPAT_VERSION"></span><a class="reference internal" href="PROJECT_COMPAT_VERSION.html#variable:PROJECT_COMPAT_VERSION" title="PROJECT_COMPAT_VERSION"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">PROJECT_COMPAT_VERSION</span></code></a>
variable.</p>
</section>


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